GreenAir® is the leader in Ultrasonic Essential Oil Diffusers serving the marketplace for the last 10 years. The diffusers by GreenAir® use the cold air diffusion technology through a vibrating electronic membrane that atomizes oil into micro particles. GreenAir® manufacturers the Ultrasonic diffusers that work perfectly with therapeutic grade essential oils and are free of BPA. BPA stands for Bisphenol A, an industrial chemical used to make certain plastics and resins and there are high chances of them seeping into the food or beverages stored in the plastic container. Therefore, the essential oil placed in the GreenAir® diffusers do not encounter BPA contamination—they are BPA-free.